Jennifer Arnold's heartfelt and idealistic documentary celebrates the remarkable effect of a small – actually, not so small – act of altruism. In the 1960s and 70s, a Swedish woman called Hilde Back participated in a charity that sponsored Kenyan schoolchildren. Donating the equivalent of around £20 a month, she made a real difference. Her sponsored boy, Chris Mburu, became a lawyer and UN diplomat and was inspired to set up a scholarship in Hilde's name. Tracking her down, he discovered Hilde's own remarkable story. This is a very straightforward, unironic tale of how altruism and the doing of charitable things creates butterfly wingbeats of good that in turn create more good things: better things, evidently, than are created by Kenya's posturing and self-serving politicians. Yet the new scholarship brings its own problems. A better life for those who make the grade in an exam creates agonising moments for those who just fail – more intense misery, perhaps, than the gloom of general, inescapable poverty that existed before.